The newspaper understands that the Londoners paid a fee of £4 million to secure the Argentine's services for the year.

West Ham boss Slaven Bilic has told the Daily Mail that he wants to bring one more signing into the club this summer so they are fully prepared for the busy schedule ahead of them.

West Ham manager Slaven Bilic

The Croatian elaborated on his transfer plans further, when writing his column for the Evening Standard, highlighting midfield as an area where he would still like to strengthen:

"Maybe we go for one more in midfield if, hopefully, we qualify for the Europa League group stage but it won’t be a huge transfer."

Meanwhile, Bilic has had his say on the Hammers' club record signing Andre Ayew, labelling the Ghanaian international as a game-changer, when speaking to ITV Sport:

West Ham's new signing Andre Ayew

"He adds more quality. He came to England and did a really good job. He scored 12 goals and played in different positions. He can be a game changer."

And finally, the Hammers' summer-long battle to bring Carlos Bacca to the club looks to have ended in disappointment, as the player has reportedly opted to stay with AC Milan, according to the Evening Standard.

West Ham have, however, recruited two other forwards in the form of Ayew and Calleri, whilst Diafra Sakho has still not left the club, so there should still be plenty of goals in their forward line.